Transcript Thinking Like a Scientist

Thinking Like a Scientist
Important facts about
experimenting and the scientific
method.
The Steps of the Scientific Method







State the problem or question
Research your problem – collect information.
Develop a hypothesis.
Test your hypothesis.
Record and Analyze your data.
State your conclusions.
Replicate Work
 The
Scientific Method is really just
a process of logical thinking.
Each experiment must meet
certain criteria in order for it to
stand up to the scientific method.
If it doesn’t, then the experiment
is not valid.
Step One
The Question or Problem to be solved.
 This
is the most important part of
scientific problem solving. You
must pick a question that actually
asks a question that can be
tested and measured through the
scientific method!
 For
instance, the question “Is
Pink Pretty?” is not a question
that you can answer through
the scientific method. The
question must be one that
requires you not to ask
opinions, but to scientifically
test and measure the answer
to the question.
 Let’s
look at some more
questions and decide if they are
good Scientific Questions. Ok?
1. Does my brother like peanuts or
peanut butter better?
Good or Bad
 BAD!!!!
In Fact, HORRIBLE!!
Not only does no one care at all, but it’s
not a question that can be tested,
measured and retested!
 Here’s an important point, by the way,
each experiment must be repeated at least
 THREE TIMES!!!!!!!!!

How many times?
3
At least three and sometimes more.
AND actually TEN or MORE is better!
 Let’s
look at some more
questions and decide if they are
good science questions or bad.
2. Does water boil faster with or
without salt added?
Good or Bad
Good
– we can test & measure this one.
Does color affect the
absorption rate of
sunlight?
Good Or Bad
 Good!
Again, this is a problem
that you can establish a
procedure, test and then retest.
Step Two
Research the problem or question.
The research doesn’t have to be long, just
some basic preliminary information about
your topic. For instance, if you were doing
a question related to gravity, you would
want to find out what gravity is and why it’s
important.
Step Three
Develop a hypothesis
A hypothesis is simply your best
guess as to what the answer to
your problem is.
For instance, if your question was
Does hot water or cold water
freeze faster? Your hypothesis
will either be………
If I freeze cold and hot water then hot
water will freeze faster than cold
water.
Or
If I freeze cold and hot water then cold
water will freeze faster than hot water.
YOUR HYPOTHESIS DOES NOT NEED TO BE
CORRECT!!!!
A
hypothesis must ….
 1. BE TESTABLE
 2. BE MEASURABLE: avoid words
like “better” or “the best”. These
are not able to be measured
quantitatively.
 3. SHOW A COMPARISON
between the experimental and
control groups
A
HYPOTHESIS is a best guess,
not a correct guess. It’s ok if you
were wrong. That’s part of the
scientific method! Some of the
best projects have had an
incorrect hypothesis. The main
idea is to use the scientific
method to solve a problem.
Another example, if you will…
Question: Do bean seeds sprout
more quickly than corn seeds?
Hypothesis:
If bean seeds and corn seeds are
planted, then corn seeds will sprout
more quickly than bean seeds.
Or
If bean seeds and corn seeds are
planted, then…………
Let’s Practice
Controls and Variables
Variables – A changeable factor in an
experiment. You should only test one
variable at a time.
Control group – The standard used for
comparison. The control group does not
contain the independent variable. It is the
“normal” one.
CONSTANTS- anything that must be kept
the same for the experiment to be fair or
valid.
ANYTHING THAT IS NOT THE
INDEPENDENT VARIABLE!!!!!

There are two types of
variables:
INDEPENDENT VARIABLE
and the
DEPENDENT VARIABLE
You should only have one INDEPENDENT
VARIABLE in any experiment.
It’s easiest to remember it this
way. What you change,
control, or adjust is always the
independent variable.
Let’s look at an example…
Let’s return to the problem earlier of

Does hot water or cold water freeze faster?
 In
this question, what you change or
adjust is the hot or cold water. That
means that using hot or cold water is
your independent variable. The water
freezing time is dependent upon
whether the water is hot or cold.
Therefore, the dependent variable in
this problem is the rate at which the
water freezes.
 Remember,
what you change is
the (“I” change) independent
variable, whatever you measure
or the outcome is the dependent
variable.

Let’s look again at the corn and bean seed
question and pull out the two types of
variables.

The problem: Do bean seeds or corn seeds
sprout more quickly?
In this problem the rate (or how quickly) at
which the seed sprouts depends on if the
seed is a bean seed or a corn seed.
Therefore, the dependent variable is the rate
at which the seed sprouts. The independent
variable (what you control or change) is the
type of seed used, corn or bean.
 Make sense? Well, let’s try one example
together.

 Problem: Is coke or sprite more acidic?
 Hypothesis:
If coke and sprite are
tested then coke will be more acidic
than sprite.
 Variables: Try now to figure this part out
and then click to see if you are correct.

The independent variable (what you
control) is the type of soda or liquid tested.

The dependent variable is the acidity (or
how much acid) of the coke or sprite.

The amount of acidity depends on whether
it is coke or sprite.
 If
all else fails, then try this approach.
 “I
Choose” the “Independent
Variable”. Notice the I in I
Choose and the I in
Independent Variable. Maybe
this will help you remember
which is which.
 Now,
the constants are easy.
These are the things within the
experiment that you keep the
same throughout each test.
 For
example, let’ return to the
problem of does a corn seed
sprout faster than a bean seed?
 The
only thing that is allowed to
change is the type of seed: Corn
or bean.
 Everything
else must remain
constant (or the same). Would it be
fair to soak the bean seed for 2
hours before testing how quickly it
grows and the corn seed only an
hour? NO!

Would it be fair to wrap the bean seed in a
paper towel and leave the corn seed on
the table?
NO!
 You
see, in order for the scientific
method to work, everything except
the independent variable must be
exactly the same. EXACTLY! That
is the Scientific Method!
 Now,
try to think of all of the
constants that you would have to
consider if you were doing the
problem of
 Does
hot or cold water freeze faster?
After you have decided
what your question is and
how to test it, you should
write a procedure for how
you will run your test.
 Now,
you are ready to begin
your procedure. Your procedure
is extremely important because
science requires that if your
project is valid, anyone in the
world should be able to follow
your procedure and end up with
the same results 100% of the
time! That’s right! 100%!
 Therefore,
your procedure should
be a step by step (listed 1, 2, 3, 4,
etc).
 Be
as detailed as possible and
don’t leave a single thing out.
Your teacher will help you set up
your procedure.
Step Four
Test Your Hypothesis
 Ok,
now your problem is chosen,
you’ve researched your problem,
developed a hypothesis and
written your procedure. What’s
next? You guessed it, it’s finally
time to actually do the
experiment!
 Follow
your procedure to a T.
If you mess up, start over.
Take pictures as you go as
data and proof of your work.
Keep a careful record and
maybe keep a journal of the
experience.
Step Five
Record and Study Data
 While
doing the experiment, you
must create some type of chart to
keep track of what happened in
your experiment during each of
your three tests.
Next,
study your charts
(data) to see if the
experiment turned out the
way you thought it would
(your hypothesis).
Step Six
Draw a Conclusion

Finally, it’s time to draw some conclusions.
What did you find out? Did the data
support your hypothesis or not?

Example: Let’s use the corn seed and
bean seed experiment. If the corn seed
did indeed sprout first I would write a
conclusion stating…
The
data collected
supported my hypothesis.
The corn seed sprouted
faster than the bean seed,
so I do think there is a
relationship between the
type of seed and sprouting
time.
 Any
extra conclusions that
were drawn during the
experiment can also be listed
under your conclusion.